Originally Posted by Norcoredneck
You can thread nipples in and use conduit nuts to lock them in.
Nuts come in bag from Home Depot/Lowes, ect. Found in electrical section.
Or you can use Plugs. (Thanks Swampb.)
Plugs are drilled and screws and double nuted for easy removal.
Also in electrical isle at Home Depot/Lowes.
I was looking at the nuts earlier today at HD and they said steel. No mention of galvanized. Those still ok?
Plugs - how do you open them up if you need additional airflow?